[jira] [Assigned] (HIVE-14450) Vectorization: StringExpr::truncate() can assume 1 byte per-char minimum

["Teddy Choi (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-14450?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Teddy Choi reassigned HIVE-14450:
---------------------------------

    Assignee: Teddy Choi

> Vectorization: StringExpr::truncate() can assume 1 byte per-char minimum
> ------------------------------------------------------------------------
>
>                 Key: HIVE-14450
>                 URL: https://issues.apache.org/jira/browse/HIVE-14450
>             Project: Hive
>          Issue Type: Improvement
>          Components: Vectorization
>    Affects Versions: 2.2.0
>            Reporter: Gopal V
>            Assignee: Teddy Choi
>
> {code}
> public static int truncate(byte[] bytes, int start, int length, int maxLength) {
>     int end = start + length;
>     // count characters forward
>     int j = start;
>     int charCount = 0;
>     while(j < end) {
>       // UTF-8 continuation bytes have 2 high bits equal to 0x80.
>       if ((bytes[j] & 0xc0) != 0x80) {
>         if (charCount == maxLength) {
>           break;
>         }
>         ++charCount;
>       }
>       j++;
>     }
>     return (j - start);
>   }
> {code}
> Should not read the bytes if the maxLength is 4096 and the input string has 256 bytes.



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